Car navigation apparatuses, smartphones, and other electronic instruments that present a road map to a user, search for a route to a destination, and guide the user along the road to the destination are known as an information processing system that performs a process by using map data. Further, it is known that some of these electronic instruments update locally stored map data in accordance with data received from a distribution center.
Moreover, known map data has a hierarchical structure that includes a plurality of layers of data. It is known that the data in the lowest layer includes detailed road network information such as information about superhighways, national roads, major local roads, prefectural roads, and minor streets, and that the data in a high layer includes information about major road networks only (refer to Patent Literature 1).